Use it... it's not like you're paying steam for it, in fact they already got paid for the game, you'd be doing them a favor by NOT using it and not using bandwidth.

What do you mean "any thoughts"?
How about "stop being a pillock and play the damn thing"? It's free. What does it matter if the evil valves be stealing your accounts when you'd otherwise just never play it anyway?

I agree with Sielle. Use it. If you're not actually giving Steam any money, where's the drawback (other than maybe getting close to or over your monthly bandwidth cap if you have one)?

Why worry about it when it's free!

Well, there's little harm in installing a free game... even if by some freak accident Steam decides to disable your account, you don't lose anything you really care about, right?
I suggest doing the same thing you did for HL2 - install, enjoy, delete.

You should donate it to a homeless person.

Despite my current problems with Steam (which are still ongoing *sigh*) you simply cannot pass up one of the best games of the year and one of the best Comic Book licences ever. Especially for free. If anything just use Steam for Arkham and any Valve games, you lose nothing.

I think you should just give it to me.

Give it to me, a person with an okay PC who has 3D Vision and no problem with Steam! I would love to play Batman with DRM-Infested Rental-Riddled stEAm slicing my wrists for me.

Use it.
When and if your account is disabled for any reason, complain to the people that gave the game : Tell them Steam are evil incarnate, and have locked you out of the game they so generously gave you for purchasing their fine equipment, and let them deal with Steam CS :P

Any thoughts ? Any...thoughts ?
Good God man, run like hell. That's obviousouly some evil Valve plot ;)
Seriously, as much as i dislike steam i have to say go for it and enjoy both the game and the new rig.

This is my favourite answer.
I am of course, going to bite the bullet and use steam for this one-off... I mean, it's £30+ of free game that I don't really want to turn down for no good reason.
It does annoy me that Steam is required though, I had hoped that I would get an OEM DVD copy, like the copy of Assassins Creed that I also got (can't remember what that came with...). I have concerns about the market share that Steam currently has, especially since it is quite often DRM heavy.
nVidia do seem to offer various games as digital downloads, but in my brief viewing of their store I couldn't see what you needed to download them with, I would assume Steam if they have this partnership.
[edit] installing steam, it asks for language, I couldn't see English for a while, until I realised it was the US flag I needed to look for... Where's my proper British English Valve?!? :P The reasons against Steam just stack up! ;)

You should be more annoyed that, in spite of requiring Steam, it still also requires activation limited secuROM DRM. But it seems that it returns activations on a monthly basis, so it shouldn't be a problem. It's still an unnecessary slap in the face though.

Securom....
That's the only relevant issue you should be grappling with.